1. Field of the Invention
The present invention relates to a method and apparatus for press-fitting caps on electronic parts and the like and, more particularly, to an improved method and apparatus for press-fitting caps to be used as electrode terminals on both ends of each electronic part, such as a resistive component rod of a small-sized resistor.
2. Description of the Prior Art
In such small-sized electronic parts as small-sized resistors, the component rod is usually about 6 mm in length and about 1.5-2 mm in diameter, and the cap is about 2-3 mm in length and about 2-2.5 mm in diameter. For the purpose of press-fitting these caps on such rods, it has been a usual practice to adopt the following apparatus and method.
The rods are suitably fed and placed in lateral grooves provided on the circumference of a wheel and thereby are conveyed. Caps suitably supplied are held by a chuck adapted to be three-dimentionally driven by a cam system. The chuck is intermittently operated to press-fit the caps on the rods.
This apparatus, however, is complicated in construction and operation. The operating stroke of the chuck is large. Therefore, the high-speed operation of the apparatus is limited and a production of about 200 to 300 products per minute is possible at most.
In the usual cap-feeding means heretofore used, caps are gravitationally transferred from a cap supply source, or a cap container, onto a pair of cap-conveying wheels so that they are placed one by one in the lateral grooves provided on the internal sides of the circumferences of the respective cap-conveying wheels. It seems possible to provide a rod-feeding means in the same manner as with the cap-feeding means by gravitationally transferring the rods onto a rod-conveying wheel so that the rods are placed one by one in the lateral grooves provided on the circumference of the rod-conveying wheel. However, provision of such rod-feeding means makes it difficult to afford a sufficient space between the upper side of each cap-conveying wheel and that of the rod-conveying wheel for providing a guide device for making the rods gravitationally fall. In addition, it is also difficult to sufficiently widen such a space, because, if this space is widened, the operation of fitting the caps on the rods will be hampered.